This invention relates to linear ester carbonate copolymers that contain carbonate groups, phosphorus groups and ester groups in the linear chain.
Polyestercarbonates, formed by the reaction of a diol with a dicarboxylic acid or diacid halide and phosgene, have been described for example in U.S. Pat. Nos. 3,030,331; 3,169,121; 3,220,976; 4,156,069; 4,278,787; 4,330,662 and 4,360,656. The polyestercarbonates, such as those derived from bisphenol-A, phosgene, and terephthaloyl and isophthaloyl chloride, generally exhibit higher heat resistance compared to bisphenol-A polycarbonate. As a result of this increased heat resistance, the polyestercarbonates generally require higher fabrication temperatures and are targeted for higher temperature end-use applications as compared to bisphenol-A polycarbonate. However, the increased fabrication and end-use temperatures can lead to deterioration of the polyestercarbonate, as evidenced by discoloration and decreases in molecular weight.
In view of the aforementioned deficiencies of conventional polyestercarbonates, it would be highly desirable to provide a polyestercarbonate of essentially the same or similar monomeric materials as are known in the art wherein improved thermal-oxidative stability is obtained without the necessity of blending post-polymerization additives with such a polymer. In addition to eliminating an additive blending step, it is desirable to provide a more uniform distribution of stabilizer moieties, a reduced probability of extracting or leaching the stabilizer moieties from fabricated articles, and a low level of stabilizer moieties in order that the desirable properties of conventional polyestercarbonates are not sacrificed.